Search
Now showing items 1-10 of 10
Article
A spectral radius type formula for approximation numbers of composition operators
(Elsevier, 2014-12-15)
For approximation numbers an(Cφ) of composition operators Cφ on weighted analytic Hilbert spaces, including the Hardy, Bergman and Dirichlet cases, with symbol φ of uniform norm <1, we prove that limn→∞[an(Cφ)]1/n=e−1 ...
Article
Some new properties of composition operators associated with lens maps
(Springer, 2013-05)
We give examples of results on composition operators connected with lens maps. The first two concern the approximation numbers of those operators acting on the usual Hardy space H2. The last ones are connected with ...
Article
Extended eigenvalues of composition operators
(Elsevier, 2021-12-15)
A complex scalar λ is said to be an extended eigenvalue of a bounded linear operator A on a complex Hilbert space if there is a nonzero operator X such that AX=λXA. The results in this paper provide a full solution to the ...
Article
Compact composition operators on the Dirichlet space and capacity of sets of contact points
(Elsevier, 2013-02-15)
We prove several results about composition operators on the Dirichlet space D⁎. For every compact set K⊆∂D of logarithmic capacity , there exists a Schur function φ both in the disk algebra A(D) and in D⁎ such that the ...
Article
Compositional universality in the N-dimensional ball
(De Gruyter, 2007-05)
It is proved in this note that a sequence of automorphisms on the N-dimensional unit ball acts properly discontinuously if and only if its corresponding sequence of composition operators is universal on the Hardy space of ...
Article
Monsters in Hardy and Bergman spaces
(Taylor & Francis, 2002)
A monster in the sense of Luh is a holomorphic function on a simply connected domain in the complex plane such that it and all its derivatives and antiderivatives exhibit an extremely wild behaviour near the boundary. In ...
Article
Approximation numbers of composition operators on the Hardy space of the infinite polydisk
(Springer, 2017-12)
We study the composition operators of the Hardy space on D∞ ∩ℓ1, the ℓ1 part of the infinite polydisk, and the behavior of their approximation numbers.
Article
Approximation numbers of composition operators on Hp
(De Gruyter Open, 2015-01)
We give estimates for the approximation numbers of composition operators on the Hp spaces, 1 ≤ p < ∞.
Article
On approximation numbers of composition operators
(Elsevier, 2012-04)
We show that the approximation numbers of a compact composition operator on the weighted Bergman spaces Bα of the unit disk can tend to 0 arbitrarily slowly, but that they never tend quickly to 0: they grow at ...
Article
Extended eigenvalues of composition operators
(Elsevier, 2021-12-15)
A complex scalar λ is said to be an extended eigenvalue of a bounded linear operator A on a complex Hilbert space if there is a nonzero operator X such that . The results in this paper provide a full solution to the problem ...